After-run Pump - Idea for regular triggering

[macspring]

An idea for regularly triggering the after run pump occurred to me. What do people think of this ?

As I understand it, the idea of the after-run pump is to pump water around the cooling system to cool the engine and turbo for longevity.

On my short but testing journeys, the after run pump never appears to cut in when the engine is turn off, and so I've thought of wiring in the trigger wire for the after-run pump, through a relay, into the circuit that stays live in the loom on a timer in the car for say the electric windows.

Would also be cool for the radio also, where you can leave the radio on as you get out of the car and have already taken out the key, one can then walk away and the radio turns off when the circuit times out.

Does anyone have anymore information about this circuit, what is it for, and how it times itself out ?

Does any of this make sense ?

Thanks for any comments.

[UrS4boy]

Does anyone have anymore information about this circuit, what is it for, and how it times itself out ?

Here is some info that might help you:

http://forums.quattroworld.com/s4s6/msgs/21503.phtml

[djh]

Another option is using a cheap ebay turbo timer to run this rather than keep the engine running as you can have full setup functions inside the car.

[UrS4boy]

Another option is using a cheap ebay turbo timer to run this rather than keep the engine running as you can have full setup functions inside the car.

True. But why bother? The factory after-run system runs when it has to, which is not every time. After a hot run on the highway, you should be manually cooling the car down anyway, i.e. driving slowly through town, on the way home.

[djh]

Agree.

When I first joined another audi site there was talk about turbo timers not being needed on our cars because of the afterrun system and I can see people's points.

Only thing i'd be inclined to do is fit a switch so that I could start the fans up in traffic if need be as an extra failsafe if it was needed. Aircon people have already got this on s2's as you just switch this on and the fan starts up.

[johne]

An idea for regularly triggering the after run pump occurred to me. What do people think of this ?

The commonest way I've heard of is to put a fuse between the contacts on the temperature sensor in the water manifold that triggers the after-run circuit, that way the after-run pump will run for 10 mins or so everytime you turn off the engine. All you're really doing is shorting out the temperature sensor.

As to whether it's worth it, there's been lots of debate on here as you can find with the search function. Some worry that 10 mins of the pump and radiator fan every time you stop the engine will flatten the battery, some have fitted a temperature sensor that triggers at a lower temperature than the standard one at 105 degrees C. In the end most of us appear to have survived the best part of 200,000 miles without the circuit having ever actually run and still on our original turbo

Like a lots of things, I guess it depends how hard you drive............

John

[JP]

I changed the two pin switch to a lower threshold on my watermanifold and my after run system runs for 10min max on the relay even if it doesn't bring it back down below the lower threshold. Part no. Is on a thread somewhere on forum. Without following the link posted earlier in thread (on my phone) its prob in there. Its of a transporter iirc.

As for turbo timers despite them bringing me engine rebuild work in the early days I don't condone them. Any form of prolonged idling be it during warm up (even worse) or cool down causes premature engine wear from unburnt fuel caused by the gradual fouling of the plugs on turbo cars. Leading to bearing failure, guide wear, bore wear and small end bush wear from fuel abrasives in the oil over time.

[A80Avant]

i agree with JP here.
i have done this many years ago and the temp sender is 90 to 80C instead of 105 to 95 and it works most of the times after a run keeping the temps down. Having it there for more than 4 years i must say that turbowise, i havent seen any damage due to that on the turbos i have used.

[UrS4boy]

As for turbo timers despite them bringing me engine rebuild work in the early days I condone them. Any form of prolonged idling be it during warm up (even worse) or cool down causes premature engine wear from unburnt fuel caused by the gradual fouling of the plugs on turbo cars. Leading to bearing failure, guide wear, bore wear and small end bush wear from fuel abrasives in the oil over time.

I am confused. You say you condone turbo timers as in "to accept and allow (behavior that is considered morally wrong or offensive) to continue", yet you describe the reasons why they are bad. What am I missing? Why condone them if they are bad?

[JP]

Sorry should read "don't" joys of predictive typing on phones. Editing now.

[rynaqui]

Think he might have made a mistake, thanks for more advice everyone.

I was already letting the car cool down, is it ok to use the ac button for a few minutes before coming to a stop?

[johne]

Yes, it's fine but I don't see what difference it will make when the engine is running. With the engine running, the water pump is circulating coolant cooling the turbo. Whether the radiator fan is running on no.1 speed due to the A/C or not won't make any difference. If the coolant is too warm the radiator fan will cut in anyway at speed no.2.

John

[AndyP]

I changed the two pin switch to a lower threshold on my watermanifold and my after run system runs for 10min max on the relay even if it doesn't bring it back down below the lower threshold. Part no. Is on a thread somewhere on forum. Without following the link posted earlier in thread (on my phone) its prob in there. Its of a transporter iirc.

As for turbo timers despite them bringing me engine rebuild work in the early days I don't condone them. Any form of prolonged idling be it during warm up (even worse) or cool down causes premature engine wear from unburnt fuel caused by the gradual fouling of the plugs on turbo cars. Leading to bearing failure, guide wear, bore wear and small end bush wear from fuel abrasives in the oil over time.

This is the thead with the part numbers in for the lower temp switch

http://www.s2forum.com/forum/showthread.php?t=4070

I've got this one mine, but I still think it needs a switch in there to over rule it if required. The pump will come on every time and if you're doing a lot of short journeys it can hammer the battery. Plus in the winter time I don't think it's really necessary.

[macspring]

Completely forgot about the lower temperature threshold switch option.

Don't want to leave it idling, apart from the reasons stated by JP, I don't have the time, and as journeys are only 3 or 4 miles, don't want to restrict myself from boosting in the last mile of the journey, so the lower temperature switch is the one for me.

Anyone got anymore information about the circuit that allows the windows to operate for a while, before timing out, after the engine is turned off and the key withdrawn ?

Thanks.

[johne]

Anyone got anymore information about the circuit that allows the windows to operate for a while, before timing out, after the engine is turned off and the key withdrawn?

It's part of the double relay (J139) that controls the windows and allows you to operate the windows and sunroof for around a minute after you've turned off the ignition unless or until you open a door. You can tell it's active as the window switches are kept illuminated.

John